The "Class II MHC Gene Control and Disease Relevance" conference will focus on recent advances in class II MHC gene control, and its applicability to multiple immunologic-diseases. This is a timely conference because many recent advances have been made in the regulation of class II MHC expression. In addition, the applicability of this knowledge to manipulate diseases where class II MHC plays an important role seems imminently feasible. A meeting that merges interests in class II gene control and disease control is long overdue since the last meeting that was somewhat relevant to these topics was held in Madrid in 1996. The field of class II MHC gene control has undergone an explosion of knowledge, which is relevant to a wide variety of clinical diseases, including autoimmunity, microbial infections, transplantation, immunodeficiency, immunologic and neurologic-inflammatory diseases and cancer development and therapy, to name a few prominent examples. All the major transcriptional regulators of class II MHC genes are now identified. Several of the gene products are missing in different subgroups of the Bare Lymphocyte Syndrome or in vitro generated mutant cell lines. These include the RFX-5, RFXAP, RFXB-RFXANK factors. In addition, a master switch that controls all class II MHC genes, the class II transactivator (CIITA) has been isolated, and has high relevance in many diseases. The mechanism of how class II MHC genes are controlled are becoming increasingly clear, where CIITA serves as a focal point for other transcription factors. Interfering with these interacting sites provide great potentials for manipulating class II MHC gene expression, and disease outcome. This meeting is intended to bring immunologists in two divergent areas (diseases or disease models and MHC gene control) to stimulate new approaches to control a divergent number of diseases where MHC plays a critical role.